Collapsible mandrel for manufacturing reinforcing cages



R. D. THOMAS 2,861,602

COLLAPSIBLE MANDREL FOR MANUFACTURING REINFORCING CAGES Nov. 25 195 8 3Sheets-Sheet 1 Filed Dec. 21, 1956 F IG. 1

INVENTOR. RALPH D. THOMAS BY ATTORNEY R. D. THOMAS COLLAPSIBLE MANDRELFOR MANUFACTURING REINFORCING CAGES Filed Dec. 21, 1956 Nov. 25, 1958 3Sheets-Sheet 2 INVENTOR.

FIG. 2

RALPH D. THOMAS ATTORNEY R. D. THOMAS 2,861,602

COLLAPSIBLE MANDREL FOR MANUFACTURING REINFORCING CAGES Nov. 25, 1958 3Sheets-Sheet 3 Filed Dec. 21, 1956 INVENTOR. RALPH D. THOMAS BY ATTORNEYUnited States Patent COLLAPSIBLE MANDREL FOR MANUFACTURING REINFORCIN GCAGES Ralph D. Thomas, Miami, Fla., assignor to Anna M. Sedges, MiamiBeach, Fla.

Application December 21,1956, Serial No. 629,970

1 Claim. (Cl. 14092.2)

This invention relates to mandrels generally and is more particularlydirected to collapsible mandrels utilized in the manufacture ofreinforcing cages to be placed in poured concrete piling, columns andthe like.

A principal object of the present invention is to provide a collapsiblemandrel for the production of reinforcing cages which readily releasethe cage from the mandrel along their four sides after being formed andwelded to permit the removal of the reinforcing cage from the mandrelwith ease.

A further object of the presentinvention is the provision of acollapsible mandrel for manufacturing reinforcing cages described asabove which permits the production of cages of any desired length,weight or size.

A still further object of the present invention is to provide acollapsible mandrel characterized as above having any number of sidesso. as .to produce reinforcing cages of any desired polygonal crosssection.

A still further object of the present invention is to provide acollapsible mandrel consisting of a plurality of inner and outer nestingangle bars mounted on a rotatable shaft for producing reinforcing steelcages which when formed thereon is released for removal by shifting theouter nesting angle bars in the direction of the inner nesting bars.

With these and other objects in view, the'invention will be bestunderstood from a consideration of the following detailed descriptiontaken in connection with the accompanying drawings forming a part ofthis specification, with the understanding, however, that the inventionis not confined to any strict conformity with the showing of thedrawings but may be changed or modified so long as such changes ormodifications mark no material departure from the salient features ofthe invention as expressed in the appended claim.

In the drawings:

Figure 1 is a perspective view of a collapsible mandrel embodying myinvention with a reinforcing cage shown in part and in position asmanufactured thereon with the mandrel in its contracted condition forremoval of the cage.

Figure 2 is a top plan view thereof with the mandrel shown in itsexpanded condition.

Figure 3 is a cross sectional view taken along the line 33 of Figure 2,with the mandrel in its contracted position shown by dotted lines.

Figure 4 is an exploded view thereof with the reinforcing cage notshown.

Figure 5 is a perspective view of a completed reinforcing cage as seenwhen removed from the mandrel.

Referring to the drawings wherein like numerals are used to designatesimilar parts throughout the several views, the numeral refers generallyto my collapsible mandrel consisting of a main shaft 11 whose ends aremounted on supports (not shown) and provided with power operated drivemechanism (also not shown) for rotating the mandrel 10 in themanufacture of reinforcing cages as is explained in greater detailhereinafter. Mounted 2,861,602 Patented Nov. 25, 1958 on the shaft 11 isa plurality of support members or plates 12 equally spaced therealongand welded or otherwise secured to the shaft 11 at their mid-portions soas to become integral therewith. The outer periphery of the supportplates 12 is provided with recesses 13 to receive therein angle bars orirons 14. There is shown, by way of illustration, four such angle bars14 mounted in parallel relation with each other and with the rotatableshaft 11. However any desired number of such angle bars 14 may beutilized depending upon the desired cross-sectional configuration of thereinforcing cages that is to be produced thereon. For example, if onlythree angle bars 14 are used, the reinforcing cage that is to beproduced will then the cage will have five sides, if six angle bars 14are used, then the cage will be hexagonal in cross section, etc.

Each of the angle bars 14 is provided with leg portions 14A and 14B setat approximately right angle to each other. In nesting relation witheach of the angle bars 14 there is positioned a similar angle bar 15lying along the full length of the angle bars 14'having leg portions 15Aand 15B lying in parallel relation with the leg portions 14A and 14B ofthe angle bars 14. The sliding movements of the outer angle bars 15 withrelation to the inner angle 1 bars 14 are limited by virtue of aplurality of stop members 16 welded or otherwise secured to theouter-edge portions of the outer angle bars 15 and extending inwardlythrough slots 17 formed in the inner angle bars 14. The length of theslots 17 determines the length of. travel of the outer angle bars 15 onthe inner angle bars 14. A pin 18 which is mounted at the free end ofeach of the stop members 16 prevents the nesting angle bars 14 and 15from becoming inadvertently separated. Means are provided for collapsingand expanding the outer angle bars 15 comprising a plurality of Wedges19 mounted on each of the leg portions 14A and 14B of the inner anglebars 14 and a plurality of similarly positioned wedges 20 on the legportions 15A and 15B of the outer angle bars 15. The Wedges 19 and 20are in opposed contact relationship with their respective inclinedsurfaces 21 and 22 facing in a direction toward each other as best shownby Figure 3 and their elevated surfaces 23 and 24 mounted adjacent theinclined surfaces 21 and 22 respectively.

With the construction as described above, when the mandrel 10 is in itscontracted or collapsed position, the outer angle bars 15 are at theposition in which they are closest to the inner angle bars 14 as shownby Figure 1 and by the dotted lines in Figure 3. In this position theinclined surfaces 21 and 22 of the wedges 19 and 20 respectively are incontact relation with each other. Also, the stop members 16 will be inabutting relation with one end of the slots 17, namely the lower end ofthe slots 17 as viewed in Figure 1. When the outer angle bars 15 areslid along the inner angle bars 14 to their other extreme positionwherein the stop members 16 abut against the other end of the slots 17,the wedges 20 will slide on the wedges 19 until the elevated surface 24of the wedge 15 has come to rest upon the elevated surface 23 of thewedge 19 during this sliding movement, the outer angle bars 15 havemoved outwardly in a direction awaffrom the main shaft 11, a distanceequal to the thickness of the Wedges 19 and 20. That distance may benoted in Figure 3 which shows the distended position of the angle bars15 in solid lines and their contracted positions I by dotted lines.

bars 15 are now in the position at which they are the farthest away fromthe shaft 11. A reinforcing steel bar 25 is placed in each of the anglebars 15 and a binding wire 26 is Wound about the mandrel 10 in spiralloops as shown by Figures 1 and 2. In practise, the shaft 11 is gearedto a source of power which slowly revolves the mandrel as the bindingwire 26 is payed out onto the outer periphery of the mandrel 10. At eachposition that the binding Wire 26 contacts the reinforcing steel rods25, they are welded or otherwise secured together. When a cage 27 asshown by Figure is formed along the full length of the reinforcing steelrods 25, the rotating movement of the mandrel is stopped. Now, the anglebars 15 are made to slide along the angle bars 14 to their contracted orcollapsed position with the inclined surfaces 21 and 22 of the wedges 19and respectively in contact relation. As a practical matter, by pullingon the completed cage 27, the angle bars 15 are made to slide(downwardly as viewed in Figure 3) until the cage becomes released fromthe angle bars 15 when the latter While sliding along the angle bars 14move in the direction of the shaft 11 on all four sides thereof. Thecage 27 is continued to be pulled from the mandrel 10 until it is freedtherefrom. The operation is again repeated by placing reinforcing rods25 in the angle bars 15 which had been placed in their distendedposition, and the binding wire 26 would thereabout to form another cage27.

Having now disclosed my invention and realizing that, in view of mydisclosure many other modifications in details and construction ordesign will readily occur to those skilled in the art, I do not chooseto limit myself except as in the appended claim.

What I claim as new is:

A mandrel for fabricating reinforcing steel cages comprising a rotatableshaft, support members mounted on said shaft and extending radially ofsaid shaft, a plurality of inner elongated bars mounted on said supportmembers, said inner elongated bars being substantially parallel to saidshaft and symmetrically disposed about said shaft, each of said barshaving a slot, a plurality of further elongated bars, each of saidfurther elongated bars having troughs for receiving longitudinallydisposed reinforcing rods and being positioned in spaced parallelrelation with one of said inner bars, a stop member mounted on each ofsaid further elongated bars and extending through said slots forlimiting the sliding movement of said further elongated bars withrelation to said inner elongated bars, a locking member mounted on eachof said stop members for preventing said stop members from leaving saidslots, a plurality of pair of Wedges mounted on said inner and furtherelongated bars in opposed relation, said wedges each having an inclinedsurface and an elevated surface whereby when said elevated surfaces ofsaid opposed Wedges are in contact relation said further elongated barsare a greater distance from said inner bars than when said inclinedsurfaces of said opposed wedges are placed in contact relationship.

References Cited in the file of this patent UNITED STATES PATENTS211,247 McVoy Jan. 7, 1879 459,265 Barton Sept. 8, 1891 1,260,786 ManzMar. 26, 1918 1,334,704 Kubasta Mar. 23, 1920 1,589,456 Beghetti June22, 1926 2,151,034 Kauppert Mar. 21, 1939 2,564,482 Kentis Aug. 14, 1951

